Glossary

Viruses composed of a nucleocapsid and a double-stranded linear DNA genome. There are 55 described types of adenovirus that infect humans, which are responsible for 5–10 percent of upper respiratory infections in children, and many infections in adults as well.

Lymphocytes that play a large role in the humoral immune response (as opposed to the cell-mediated immune response, which is governed by T cells). The principal functions of B cells are to make antibodies against antigens, perform the role of antigen-presenting cells (APCs) and eventually develop into memory B cells after activation by antigen interaction. B cells are an essential component of the adaptive immune system.

The application of computer science and information technology to the field of biology. Bioinformatics entails the use of databases, algorithms, computational and statistical techniques and theory to solve formal and practical problems arising from the management and analysis of biological data.

A molecule used as an indicator of a biological state, such as the presence of disease. Protein biomarkers, such as the one detected in the prostate-specific antigen (PSA) test, for example, can predict the development of cancer (in this case, prostate cancer). Biomarkers could also take the form of gene expression patterns—a “snapshot” of all the active genes at a given time—or the presence of specific gene mutations, which may dictate a treatment regimen.

A single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences, found in the nucleus of cells. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.

Small cell-signaling protein molecules that are secreted by the glial cells of the nervous system and by numerous cells of the immune system and are a category of signaling molecules used extensively in intercellular communication.

The study of the process by which organisms grow and develop. Such development involves complex timing of genetic events that dictate when, where, and how certain tissue grow. The field has contributed to a greater understanding of stem cells, epigenetics, and how genetic aberrations can lead to disease.

Deoxyribonucleic acid or DNA, is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms. DNA is made up of long chains of subunits called nucleotides, the sequence of these nucleotides can encode instructions for making proteins and other molecules.

The process of creating a complementary RNA copy of a sequence of DNA. The messenger RNA transcript can then be edited, used as a set of instructions in the synthesis of new proteins, or even serve in biological process directly.

Part of the overall process of gene expression. In translation, messenger RNA (mRNA) produced by transcription is decoded by the ribosome to produce a specific amino acid chain, or polypeptide, that will later fold into an active protein.

A phrase coined by Wistar researcher Meenhard Herlyn to describe the ability of any given melanoma cell to take on the role of a cell-growing cancer stem cell, thereby replenishing tumors that may otherwise have been decimated by targeted therapeutics.

A process that causes epithelial cells to change into mesenchymal cells, which carry with them capabilities often associated with metastic cancers. Studying this transition can help researchers design new therapeutics to stop the progress of metastatic cancer.

Type of cell that synthesizes the extracellular matrix and collagen, the structural framework for animal tissues, and plays a critical role in wound healing. Fibroblasts are the most common cells of connective tissue in animals.

Proteins found in the cell nucleus that package and order the DNA into structural units called nucleosomes. They are the chief protein components of chromatin, acting as spools around which DNA winds, and play a role in gene regulation. Proteins that modify or alter histones can, in turn, modify or alter gene expression.

A complex response to infection, wounds, or other irritants by cells to initiate the healing process. Without inflammation, wounds or infections could never heal. Inflammation can also contribute to the spread of certain types of cancer, either by helping to sustain the tumor microenvironment or suppressing the immune response to tumors.

Consists of the cells and mechanisms that defend the host from infection by other organisms in a non-specific manner. This could come in the form of barriers to infection, such as skin, or to “complementary” proteins that aid in the general immune response.

As non-protein coding transcripts longer than 200 nucleotides. They are non-coding in the sense that they do not encode proteins; instead they can have an effect on cellular processes on their own. Wistar’s Ramin Shiekhattar, Ph.D., has determined that these RNA molecules can have a promoter effect on particular genes, signaling the cell to “read” specific gene sequences.

Is a malignant tumor of melanocytes. Melanocytes are cells that produce the dark pigment, melanin, which is responsible for the color of skin. They predominantly occur in skin, but are also found in other parts of the body, including the bowel and the eye. Melanoma can occur in any part of the body that contains melanocytes.

Is the set of chemical reactions that happen in living organisms to maintain life. Broadly speaking, metabolism is the process by which organisms transform food into energy and use that energy to create new proteins and other molecules. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments.

In humans, it is a tumor suppressor protein involved in Neurofibromatosis type II, a familial cancer disorder. NF2 is typically caused by mutations in the merlin (Moesin-Ezrin-Radixin-Like Protein) gene.

A viral disease that causes acute encephalitis (inflammation of the brain) in warm-blooded animals. In the 20th century, The Wistar Institute created two new rabies vaccines: an improved vaccine for humans and an oral vaccine that can be used in baits to vaccinate wildlife.

Like DNA, RNA is made up of a long chain of components called nucleotides. RNA molecules play an active role in cells by catalyzing biological reactions, controlling gene expression, or sensing and communicating responses to cellular signals. Unlike DNA, most RNA molecules are single-stranded. Single-stranded RNA molecules adopt very complex three-dimensional structures, since they are not restricted to the repetitive double-helical form of double-stranded DNA. RNA is made within living cells by RNA polymerases, enzymes that act to copy a DNA or RNA template into a new RNA strand through processes known as transcription or RNA replication, respectively.

The most common cause of severe diarrhea among infants and young children, and a leading cause of death of children in developing nations. The Wistar Institute worked with Paul Offit, M.D., of the Children’s Hospital of Philadelphia to develop a vaccine against rotavirus.

Commonly known as German measles, is transmitted via airborne droplet emission from the upper respiratory tract of active cases. The Wistar Institute’s rubella vaccine is now part of the routine childhood vaccinations.

A region of repetitive DNA sequence at the end of a chromosome, which protects the end of the chromosome from deterioration or from fusion with neighboring chromosomes. The gradual erosion of telomeres is regarded as a key cause of aging. Cancer cells, however, often find ways to preserve their telomeres.

A way of thinking about and conducting scientific research to make the results of research applicable to the population under study and is practiced in the natural and biological, behavioral, and social sciences. Translational research transforms scientific discoveries arising from laboratory, clinical, or population studies into clinical applications to reduce cancer incidence, morbidity, and mortality.

The biological surroundings in which tumors grow. The tumor microenvironment supplies nutrients and structure to growing tumors, and often consist of otherwise healthy cells–even immune cells—that have been “co-opted” by the tumor.

A biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins.

Vehicle used to transfer genetic material to a target cell. In epidemiology, the vector could be in the form of an insect, such as the mosquito, which carries the single-cell organism that causes malaria. In molecular biology, a vector can be any virus or membrane-enclosure that can shuttle DNA to targeted cells.

The study of viruses and virus-like agents: their structure, classification and evolution, their ways to infect and exploit cells for virus reproduction, the diseases they cause, the techniques to isolate and culture them, and their use in research and therapy.